Editorial

2 pages, 165 KiB

Open AccessEditorial

by Manoj Gupta

Appl. Sci. 2020, 10(9), 3000; https://doi.org/10.3390/app10093000 - 25 Apr 2020

Cited by 6 | Viewed by 1600

The magic of the unification of different categories of materials to develop superior materials (composites) with improved functionality was recognized way back by our forefathers and was utilized very well by mother nature to support the dynamic functionality and requirements of both static [...] Read more.

The magic of the unification of different categories of materials to develop superior materials (composites) with improved functionality was recognized way back by our forefathers and was utilized very well by mother nature to support the dynamic functionality and requirements of both static and moving living organisms [...] Full article

(This article belongs to the Special Issue Metal Matrix Composite)

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14 pages, 21736 KiB

Open AccessArticle

Enhancing Properties of Aerospace Alloy Elektron 21 Using Boron Carbide Nanoparticles as Reinforcement

by Sravya Tekumalla, Ng Joo Yuan, Meysam Haghshenas and Manoj Gupta

Appl. Sci. 2019, 9(24), 5470; https://doi.org/10.3390/app9245470 - 12 Dec 2019

Cited by 4 | Viewed by 2340

Abstract

In this study, the effect of nano-B₄C addition on the property profile of Elektron 21 (E21) alloys is investigated. E21 reinforced with different amounts of nano-size B₄C particulates was synthesized using the disintegrated melt deposition technique followed by hot [...] Read more.

In this study, the effect of nano-B₄C addition on the property profile of Elektron 21 (E21) alloys is investigated. E21 reinforced with different amounts of nano-size B₄C particulates was synthesized using the disintegrated melt deposition technique followed by hot extrusion. Microstructural characterization of the developed E21-B₄C composites revealed refined grains with the progressive addition of boron carbide nanoparticles. The evaluation of mechanical properties indicated a significant improvement in the yield strength of the nanocomposites under compressive loading. Further, the E21-2.5B₄C nanocomposites exhibited the best damping characteristics, highest young’s modulus, and highest resistance to ignition, thus featuring all the characteristics of a material suitable for several aircraft applications besides the currently allowed seat frames. The superior mechanical properties of the E21-B₄C nanocomposites are attributed to the refined grain sizes, uniform distribution of the nanoparticles, and the thermal insulating effects of nano-B₄C particles. Full article

(This article belongs to the Special Issue Metal Matrix Composite)

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7 pages, 2372 KiB

Open AccessArticle

Enhanced Tensile Plasticity in Ultrafine Lamellar Eutectic Al-CuBased Composites with α-Al Dendrites Prepared by Progressive Solidification

by Jialin Cheng, Yeling Yun and Jiaxin Rui

Appl. Sci. 2019, 9(18), 3922; https://doi.org/10.3390/app9183922 - 19 Sep 2019

Cited by 5 | Viewed by 3096

Abstract

In this paper, a new class of Al-Cubased composites which combine the ultrafine lamellar eutectic matrix (α-Al + θ-Al₂Cu) and micron-sized primary α-Al dendrites was prepared by progressive solidification. By adjusting the alloy composition and solidification process, [...] Read more.

In this paper, a new class of Al-Cubased composites which combine the ultrafine lamellar eutectic matrix (α-Al + θ-Al₂Cu) and micron-sized primary α-Al dendrites was prepared by progressive solidification. By adjusting the alloy composition and solidification process, the formation of favorable microstructural and micromechanical features can be achieved. The ultrafine lamellar eutectic composite Al₉₄Cu₆ exhibits excellent mechanical properties with 472 MPa fracture strength and 7.4% tensile plastic strain. The plasticity of the ultrafine lamellar eutectic composite relies on the volume fraction and work hardening ability of micron-scale primary phase. The present results provide a new perspective for improving the plasticity of the ultrafine lamellar eutectic alloys. Full article

(This article belongs to the Special Issue Metal Matrix Composite)

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10 pages, 8021 KiB

Open AccessArticle

Effect of 0.05 wt.% Pr Addition on Microstructure and Shear Strength of Sn-0.3Ag-0.7Cu/Cu Solder Joint during the Thermal Aging Process

by Jie Wu, Songbai Xue, Jingwen Wang and Guoqiang Huang

Appl. Sci. 2019, 9(17), 3590; https://doi.org/10.3390/app9173590 - 02 Sep 2019

Cited by 7 | Viewed by 2545

Abstract

The evolution of interfacial morphology and shear strengths of the joints soldered with Sn-0.3Ag-0.7Cu (SAC0307) and SAC0307-0.05Pr aged at 150 °C for different times (h; up to 840 h) were investigated. The experiments showed the electronic joint soldered with SAC0307-0.05Pr has a much [...] Read more.

The evolution of interfacial morphology and shear strengths of the joints soldered with Sn-0.3Ag-0.7Cu (SAC0307) and SAC0307-0.05Pr aged at 150 °C for different times (h; up to 840 h) were investigated. The experiments showed the electronic joint soldered with SAC0307-0.05Pr has a much higher shear strength than that soldered with SAC0307 after each period of the aging process. This contributes to the doping of Pr atoms, “vitamins in alloys”, which tend to be adsorbed on the grain surface of interfacial Cu6Sn5 IMCs, inhibiting the growth of IMCs. Theoretical analysis indicates that doping 0.05 wt.% Pr can evidently lower the growth constant of Cu6Sn5 (DCu6), while the growth constant of Cu3Sn (DCu3) decreased slightly. In addition, the electronic joint soldered with SAC0307-0.05Pr still has better ductility than that soldered with SAC0307, even after a 840-h aging process. Full article

(This article belongs to the Special Issue Metal Matrix Composite)

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9 pages, 3236 KiB

Open AccessArticle

Effect of Deep Cryogenic Treatment on Microstructure and Properties of Sintered Fe–Co–Cu-Based Diamond Composites

by Siqi Li, Wenhao Dai, Zhe Han, Xinzhe Zhao and Baochang Liu

Appl. Sci. 2019, 9(16), 3353; https://doi.org/10.3390/app9163353 - 15 Aug 2019

Cited by 4 | Viewed by 3044

Abstract

Metal-matrix-impregnated diamond composites are used for fabricating many kinds of diamond tools. In the efforts to satisfy the increasing engineering requirements, researchers have brought more attention to find novel methods of enhancing the performance of impregnated diamond composites. In this study, deep cryogenic [...] Read more.

Metal-matrix-impregnated diamond composites are used for fabricating many kinds of diamond tools. In the efforts to satisfy the increasing engineering requirements, researchers have brought more attention to find novel methods of enhancing the performance of impregnated diamond composites. In this study, deep cryogenic treatment was applied to Fe–Co–Cu-based diamond composites to improve their performance. Relative density, hardness, bending strength, and grinding ratio of matrix and diamond composite samples were measured by a series of tests. Meanwhile, the fracture morphologies of all samples after the bending strength test were observed and analyzed by scanning electron microscope. The results showed that the hardness and bending strength of matrix increased slightly after deep cryogenic treatment. The grinding ratio of impregnated diamond composites exhibited a great increase by 32.9% as a result of deep cryogenic treatment. The strengthening mechanism was analyzed in detail. The Fe–Co–Cu-based impregnated composites subjected to deep cryogenic treatment for 1 h exhibited the best overall performance. Full article

(This article belongs to the Special Issue Metal Matrix Composite)

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10 pages, 3878 KiB

Open AccessArticle

Characterization of Copper–Graphite Composites Fabricated via Electrochemical Deposition and Spark Plasma Sintering

by Myunghwan Byun, Dongbae Kim, Kildong Sung, Jaehan Jung, Yo-Seung Song, Sangha Park and Injoon Son

Appl. Sci. 2019, 9(14), 2853; https://doi.org/10.3390/app9142853 - 17 Jul 2019

Cited by 13 | Viewed by 3156

Abstract

In the present study, we have demonstrated a facile and robust way for the fabrication of Cu-graphite composites (CGCs) with spatially-aligned graphite layers. The graphite layers bonded to the copper matrix and the resulting composite structure were entirely characterized. The preferential orientation and [...] Read more.

In the present study, we have demonstrated a facile and robust way for the fabrication of Cu-graphite composites (CGCs) with spatially-aligned graphite layers. The graphite layers bonded to the copper matrix and the resulting composite structure were entirely characterized. The preferential orientation and angular displacement of the nano-sized graphite fiber reinforcements in the copper matrix were clarified by polarized Raman scattering. Close investigation on the change of the Raman G-peak frequency with the laser excitation power provided us with a manifestation of the structural and electronic properties of the Cu-graphite composites (CGCs) with spatially-distributed graphite phases. High resolution transmission electron microscopy (TEM) observation and Raman analysis revealed that reduced graphite oxide (rGO) phase existed at the CGC interface. This work is highly expected to provide a fundamental way of understanding how a rGO phase can be formed at the Cu-graphite interface, thus finally envisioning usefulness of the CGCs for thermal management materials in electronic applications. Full article

(This article belongs to the Special Issue Metal Matrix Composite)

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14 pages, 5689 KiB

Open AccessArticle

Microstructure and Mechanical Properties of Magnesium Matrix Composites Interpenetrated by Different Reinforcement

by Shuxu Wu, Shouren Wang, Daosheng Wen, Gaoqi Wang and Yong Wang

Appl. Sci. 2018, 8(11), 2012; https://doi.org/10.3390/app8112012 - 23 Oct 2018

Cited by 18 | Viewed by 2811

Abstract

The present work discusses the microstructure and mechanical properties of the as-cast and as-extruded metal matrix composites interpenetrated by stainless steel (Fe–18Cr–9Ni), titanium alloy (Ti–6Al–4V), and aluminum alloy (Al–5Mg–3Zn) three-dimensional network reinforcement materials. The results show that the different reinforcement materials have different [...] Read more.

The present work discusses the microstructure and mechanical properties of the as-cast and as-extruded metal matrix composites interpenetrated by stainless steel (Fe–18Cr–9Ni), titanium alloy (Ti–6Al–4V), and aluminum alloy (Al–5Mg–3Zn) three-dimensional network reinforcement materials. The results show that the different reinforcement materials have different degrees of improvement on the microstructures and mechanical properties of the magnesium matrix composites. Among them, magnesium matrix composites interpenetrated by stainless steel reinforcement have maximum tensile strength, yield strength, and elongation, which are 355 MPa, 241 MPa, and 13%, respectively. Compared with the matrix, it increases by 47.9%, 60.7% and 85.7%, respectively. Moreover, compared with the as-cast state, the as-extruded sample has a relatively small grain size and a uniform size distribution. The grain size of the as-cast magnesium matrix composites is mainly concentrated at 200–300 μm, whereas the extruded state is mainly concentrated at 10–30 μm. The reason is that the coordination deformation of reinforcement and matrix, and the occurrence of dynamic recrystallization, cause grain refinement of magnesium matrix composite during the extrusion process, thereby improving its mechanical properties. Moreover, the improvement is attributed to the effect of the reinforcement itself, and the degree of grain refinement of the metal matrix composites. Full article

(This article belongs to the Special Issue Metal Matrix Composite)

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14 pages, 6364 KiB

Open AccessArticle

Microstructures of Three In-Situ Reinforcements and the Effect on the Tensile Strengths of an Al-Si-Cu-Mg-Ni Alloy

by Lusha Tian, Yongchun Guo, Jianping Li, Feng Xia, Minxian Liang, Hongbo Duan, Ping Wang and Jianli Wang

Appl. Sci. 2018, 8(9), 1523; https://doi.org/10.3390/app8091523 - 01 Sep 2018

Cited by 7 | Viewed by 2756

Abstract

In the present paper, the microstructures of three kinds of in-situ reinforcements Al-Ti-C, Al-Ti-B, and Al-Ti-B-C-Ce were deeply investigated using a combination of scanning electron microscopy, X-ray diffraction spectroscopy, and transmission electron microscopy. The effect of in-situ reinforcements on the room temperature and [...] Read more.

In the present paper, the microstructures of three kinds of in-situ reinforcements Al-Ti-C, Al-Ti-B, and Al-Ti-B-C-Ce were deeply investigated using a combination of scanning electron microscopy, X-ray diffraction spectroscopy, and transmission electron microscopy. The effect of in-situ reinforcements on the room temperature and elevated temperature (350 °C) tensile strengths of Al-13Si-4Cu-1Mg-2Ni alloy were analyzed. It is found that doping with trace amounts of B and Ce, the size of the Al₃Ti phase in the in-situ reinforced alloy changed from 80 µm (un-reinforced) to about 10 µm, with the simultaneous formation of the AlTiCe phase. The Al-Ti-B-C-Ce reinforcement which is rapid solidified, was more effective and superior to enhance the tensile strengths of the Al-13Si-4Cu-1Mg-2Ni alloy, both at room and high temperatures than those of addition other reinforcements. The room temperature (RT) strength increased by 19.0%, and the 350 °C-strength increased by 18.4%. Full article

(This article belongs to the Special Issue Metal Matrix Composite)

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9 pages, 13554 KiB

Open AccessArticle

Effect of WC Nanoparticles on the Microstructure and Properties of WC-Bronze-Ni-Mn Based Diamond Composites

by Siqi Li, Zhe Han, Qingnan Meng, Xinzhe Zhao, Xin Cao and Baochang Liu

Appl. Sci. 2018, 8(9), 1501; https://doi.org/10.3390/app8091501 - 01 Sep 2018

Cited by 12 | Viewed by 3106

Abstract

Metal matrix-impregnated diamond composites are widely used for fabricating diamond tools. In order to meet the actual engineering challenges, researchers have made many efforts to seek effective methods to enhance the performance of conventional metal matrices. In this work, tungsten carbide (WC) nanoparticles [...] Read more.

Metal matrix-impregnated diamond composites are widely used for fabricating diamond tools. In order to meet the actual engineering challenges, researchers have made many efforts to seek effective methods to enhance the performance of conventional metal matrices. In this work, tungsten carbide (WC) nanoparticles were introduced into WC-Bronze-Ni-Mn matrix with and without diamond grits for improving the performance of conventional impregnated diamond composites. The influence of WC nanoparticles on the microstructure, densification, hardness, bending strength and wear resistance of matrix and diamond composites were investigated. The results showed that the bending strength of matrix increased up to approximately 20% upon nano-WC addition, while densification and hardness fluctuate slightly. The grinding ratio of diamond composites increased significantly by about 100% due to nano-WC addition. The strengthening mechanism was proposed according to experimental results. The diamond composites with 2.8 wt% nano-WC addition exhibited the best overall properties, thus having potential to apply to further diamond tools. Full article

(This article belongs to the Special Issue Metal Matrix Composite)

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